Strigolactone modulates phenolic acid accumulation and thereby improves tolerance to UV-B stress in Rhododendron chrysanthum Pall.

Key message: Multi-omics studies have shown that strigolactone modulates phenolic acid accumulation in the leaves of R. chrysanthum and can enable it to cope with UV-B stress. UV-B stress is an abiotic stress that plants will inevitably suffer during growth and can seriously affect the normal physiological state of plants. Strigolactone, a phytohormone, has been less studied and it is important to investigate its regulation of plant growth under UV-B radiation. In the present study, we investigated the changes in leaves of Rhododendron chrysanthum Pall. (R. chrysanthum) under UV-B radiation. The leaves of R. chrysanthum were collected for widely targeted metabolomics, hormonomics, transcriptomics, proteomics and acetylated proteomics assays. The results showed that the leaves of R. chrysanthum were able to produce a large amount of differential phenolic acids with antioxidant effects under UV-B stress, the content of strigolactone was significantly elevated, and the genes and proteins involved in phenolic acid biosynthesis and strigolactone biosynthesis were significantly altered, and some of the proteins (ASP1, 4CLL7, and CCD1) underwent acetylation modification. Meanwhile, correlation analysis showed that strigolactone was strongly correlated with differential phenolic acids, which might regulate the adaptive responses of the R. chrysanthum under UV-B stress. In this paper, we investigated the effects of strigolactone on the accumulation of phenolic acid compounds and found a strong correlation between strigolactone and elevated phenolic acid levels, which provided insights into the molecular mechanism of plant regulation of phenolic acid accumulation, and facilitated the adoption of measures to mitigate the adverse effects of UV-B stress on plant growth, and to achieve the purpose of protecting plant germplasm resources.